Includes one or more segments where the player must defend someone or something that is outside of their control and can't be replaced.
Alternate names: Protection sequence, Escort mission
Name variations: Defense sequence
The first video game about Defence sequence was released on July 1989.
Otherwise this tag works nicely when the defend objective breaks the normal game flow.
This does not include "defend/escort" missions/sequences where the one you're escorting is invulnerable or otherwise less likely to die than you yourself.